Oil and gas transmission pipeline steels with high deformation capability are required for environments (earthquake zones, permafrost zones, forest heave, deep sea applications, etc.) where large strata movement may occur. When large strata movement occurs the pipeline is exposed to large plastic deformations that can result in failure. Transmission pipelines that must operate in these environmental conditions utilize a strain based design strategy to protect the pipeline from failure. This strain based design strategy for these transmission pipeline environments requires that the steel design used for pipe production must not only have the capability to withstand the high internal operating pressure but must also have good deformation resistance characteristics.
Shougang Steel has conducted research into the metallurgical design required for heavy wall X80 transmission pipeline steel with high deformation and good low temperature mechanical property characteristics. This research coupled with the production capability of the Shougang Steel’s Qinhuangdao China (Shouqin) 4.3 m heavy wide plate mill has resulted in the successful production of a cost effective low C-Nb X80 alloy design with good deformation and low temperature toughness capabilities suitable for applications such as the natural gas TCPL/ExxonMobil proposed Alaskan Pipeline Project. This paper will discuss Shougang Steel’s research and development of heavy wall X80 pipeline steel. Key process parameter and equipment capabilities of the Shouqin 4.3 m wide heavy plate mill along with heavy wall X80 production results will be discussed.